GB2416003A - Double volute casing for a centrifugal pump - Google Patents

Double volute casing for a centrifugal pump Download PDF

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Publication number
GB2416003A
GB2416003A GB0513008A GB0513008A GB2416003A GB 2416003 A GB2416003 A GB 2416003A GB 0513008 A GB0513008 A GB 0513008A GB 0513008 A GB0513008 A GB 0513008A GB 2416003 A GB2416003 A GB 2416003A
Authority
GB
United Kingdom
Prior art keywords
pump casing
volute
pump
flow splitter
passage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0513008A
Other versions
GB0513008D0 (en
Inventor
John Fleming
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Weir Pumps Ltd
Original Assignee
Weir Pumps Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Weir Pumps Ltd filed Critical Weir Pumps Ltd
Publication of GB0513008D0 publication Critical patent/GB0513008D0/en
Publication of GB2416003A publication Critical patent/GB2416003A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/445—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps
    • F04D29/448—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps bladed diffusers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/426—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

A casing 10, for a centrifugal pump, comprises a pump volute 16 having a first volute region 18 and a second volute region 20. The regions 18, 20 are separated by a flow splitter 22 which defines at least one passage 24, 26 which may allow fluid flow between the first and second regions 18, 20. The splitter 22 may be formed during a casting process, and may extend from within a discharge branch 14 into the volute 16. The casing 10 may be formed as a single component or may be axially or radially split. Passages 24, 26 may extend across a portion of, or the entire width of, the splitter 22. The casing 10 may be used in a single-stage or multi-stage centrifugal pump.

Description

1 2416003
PUMP CASING
FIELD OF THE INVENTION
The present invention relates to a pump casing, and in particular to a double volute pump casing, such as for use in a centrifugal pump.
BACKGROUND OF THE INVENTION
Single stage centrifugal pumps comprise an impeller located within a volute formed by a pump casing, wherein the volute is in fluid communication with a pump discharge branch. The impeller is secured to a shaft which is rotatably mounted via suitable bearings on the pump casing. Conventionally, fluid is drawn into the pump via a suction branch and into a central eye of the impeller, with rotation of the impeller imparting kinetic energy to the fluid causing the fluid to be driven radially outwards and into the volute. As the fluid flows within the casing the fluid pressure increases as a result of the fluid decelerating and the kinetic energy being converted to pressure. The pressurised fluid is then discharged from the volute through the discharge branch.
As the fluid is pressurized, radial thrust is produced which creates an unbalanced load on the shaft and associated bearings, which may cause damage and reduce the overall pump efficiency. In order to reduce the radial thrust, it is known to utilise a flow splitter which extends from within or in the region of the discharge branch, and into the pump volute. This flow splitter thus creates a double volute.
A pump casing incorporating a double volute is typically manufactured by a casting process, with the flow splitter being formed utilising intricately formed and positioned internal casting cores. It is difficult during casting to ensure that the casting cores are maintained in the correct position and it is common for core slippage or shifting to occur which results in a reduction in the casting quality, reducing casing integrity and consistency which ultimately may adversely effect the hydraulic performance of the pump.
It is among the objects of aspects of the present invention to obviate or at least mitigate the
aforementioned problems with the prior art.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a pump casing comprising a pump volute having first and a second volute regions separated by a flow splitter, wherein the flow splitter defines at least one passage extending between the first and second volute regions.
Preferably, the at least one passage defined in the flow splitter is formed during a casting process.
The provision of the at least one passage in the flow splitter assists in the manufacture of the pump casing in that internal casting cores utilised during a casting process to form the flow splitter, and casing, may be connected via a stem, web or the like extending through the at least one passage. This arrangement significantly improves the stability of the casting cores during the moulding process, thus avoiding undesirable core slippage or shifting and the corresponding detrimental effect on casting quality. The improved casting quality results in a better casing integrity and consistency.
The provision of the at least one passage defined in the flow splitter will permit fluid to pass between the first and second volute regions when the pump casing is in use, for example in a centrifugal pump. It would be expected that such an arrangement would unfavourably affect the hydraulic performance of the casing. However, the present Applicant has discovered from laboratory testing on pumps incorporating the pump casing of the present invention, with both high and low optimum specific speeds, that the effects on hydraulic performance are minimal. In fact, the present Applicant has discovered that the effects on hydraulic performance by the provision of the at least one passage are acceptable in consideration of the advantages offered by this particular feature of the present invention.
The at least one passage defined in the flow splitter may be plugged in order to prevent fluid flowing therethrough between the first and second volute regions.
The at least one passage may be plugged subsequent to forming the casing by a casting process. Plugging may be achieved by a suitable insert such as a suitably formed metal, plastic, polymer, composite or the like insert.
Alternatively, the at least one passage may be plugged by a portion of one or more casting cores retained in place within the at least one passage after the casing has been formed in a casting process. For example, a core web extending through the at least one passage may be retained in place. In this arrangement, the portion of the casting core intended to be retained in place may be of a suitable material, such as metal or ceramic or the like, and should be capable of withstanding the high temperatures achieved during a casting process.
Preferably, the casing further comprises a discharge branch in fluid communication with the volute.
Advantageously, the flow splitter extends from a region adjacent the discharge branch and into the volute.
Preferably, the flow splitter extends from within the discharge branch and into the volute.
The pump casing may be formed as a single component.
Alternatively, the pump casing may be split into two or more components which are adapted to be secured together, for example by bolting, clamping, welding or the like.
S The pump casing may be axially split. Alternatively, the pump casing may be radially split. The pump casing may be radially split in a vertical plane. Alternatively, the pump casing may be split in a horizontal plane.
In one embodiment of the present invention, the pump casing may be radially split and one of the at least one passage defined by the flow splitter may be aligned with the plane of the radial split. Accordingly, a portion of the passage may be located on one side of the plane of the radial split, with the remaining portion of the passage being located on the opposite side of the plane of the radial split. This arrangement advantageously permits optimum matching of the hydraulic profiles of each portion of the casing and additionally permits superior sealing of the join between the portions of the casing.
Advantageously, the at least one passage defined in the flow splitter may be provided in the form of a hole, gap, slot, throughbore, aperture or the like.
Advantageously, the at least one passage may substantially extend the width of the flow splitter.
Alternatively, the at least one passage may extend across a portion of the flow splitter. The at least one passage may extend across a central region of the flow splitter, or may alternatively extend from an edge of the flow splitter.
In one embodiment of the present invention, the at least one passage may be rectangular in shape.
Alternatively, the at least one passage may be square, circular, ovoid, trapezoidal or the like. The at least one passage may be of any shape which is suited to be formed in a casting process.
Preferably, the flow splitter defines a plurality passages extending between the first and second volute regions. In one embodiment of the present invention, the flow splitter defines two passages. This specific embodiment is particularly advantageous in that a casting core arrangement used during a moulding process will be supported against slippage in both linear and rotational directions with respect to the Solute. Additionally, the provision of two passages will minimise the effect on the hydraulic performance of the casing.
Advantageously, the volute is adapted to house a pump impeller.
Preferably, the pump casing is adapted for use in a centrifugal pump assembly. Preferably also, the pump casing is adapted for use in a singlestage centrifugal pump assembly. Alternatively, the pump casing may be adapted for use in a multiple-stage centrifugal pump. In this arrangement, the volute may be a final stage or discharge volute of the multiple- stage centrifugal pump.
Conveniently, the volute of the pump casing is a double volute.
According to a second aspect of the present invention, there is provided a pump comprising a pump casing according to the first aspect.
According to a third aspect of the present 1() invention, there is provided a pump casing comprising a double volute at least partially defined by a flow splitter, wherein said flow splitter defines at least one passage therein extending between opposing faces of the flow splitter.
According to a fourth aspect of the present invention, there is provided a method of manufacturing a pump casing, said method comprising the step of utilising a casting core in a moulding process, the casting core being formed by at least two portions connected together by a web, wherein a pump casing flow splitter is formed between the two portions of the casting core, and the web age extends through said flow splitter between opposing surfaces thereof.
Preferably, one web is provided. Alternatively a plurality of webs are provided. In a preferred embodiment, two webs are provided.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a pump casing in accordance with an embodiment of an aspect of the present invention; Figure 2 is a perspective sectional view of the pump l0 casing of Figure 1, taken along line 2-2; and Figure 3 is a perspective sectional view of the pump casing of Figure 1, taken along line 3-3.
DETAILED DESCRIPTION OF THE DRAWINGS
Reference is first made to Figure 1 in which there is shown a crosssectional view of a pump casing 10 in accordance with an embodiment of an aspect of the present invention. The casing 10 is for use in a singlestage centrifugal pump assembly and comprises a suction branch 12, a discharge branch 14 and a pump volute 16. In use, fluid enters the pump casing 10 via the suction branch 12, is pressurized by a shaft mounted pump impeller (not shown) located within the pump volute 16, and exits the pump casing via the discharge branch 14.
The pump volute 16 is of a double volute structure and defines a first volute region 18 and a second volute or 7 region 20, wherein the first and second volute regions 18,20 are separated by a flow splitter 22 which extends from within the discharge branch 14 and into the volute 16. In use, the flow splitter assists to minimize the radial thrust experienced by the impeller shaft (not shown).
In the embodiment shown, the flow splitter 22 defines two passages 24,26 which extend between the first and second volute regions 18,20. The provision of the passages 24,26 in the flow splitter 22 assists in the manufacture of the pump casing 10 in that internal casting cores utilized during a casting process to form the flow splitter 22, and casing 10, may be connected via webs extending through respective passages 24,26. This IS arrangement significantly improves the stability of the casting cores during the moulding process, thus avoiding undesirable core slippage or shifting and the corresponding detrimental effect on casting quality. The improved casting quality results in a better casing integrity and consistency.
The provision of the passages 24,26 defined in the flow splitter 22 will permit fluid to pass between the first and second volute regions 18,20 when the pump casing 10 is in use. It would be expected that such an arrangement would unfavourably affect the hydraulic performance of the casing 10. However, the present Applicant has discovered from laboratory testing on the pump casing 10, with both high and low optimum specific speeds, that the effects on hydraulic performance are minimal. In fact, the present Applicant has discovered that the effects on hydraulic performance by the provision of the passages 24,26 are acceptable in consideration of the advantages offered by this particular feature.
Alternative views of the flow splitter 22 and passages 24,26 are shown in the perspective sectional view of Figures 2 and 3. As shown, the flow splitter 22 extends across the width of the volute 16 to separate the two volute regions 18,20. Additionally, the passages 24,26 are in the form of rectangular apertures extending across the width of the flow splitter 22.
It should be understood that the embodiment described and shown is merely exemplary of the preset invention and that various modifications may be made thereto without departing from the scope of the invention. For example, the pump casing may be adapted for use in a multiple-stage pump wherein the volute 16 defines the final stage volute. Additionally, any number of passages may be provided in the flow splitter 22.
Furthermore, the passages 24,26 may be plugged by an insert to prevent fluid flowing between the volute regions 18,20.

Claims (36)

  1. CLAIMS: l. A pump casing comprising a pump volute having first and a
    second volute regions separated by a flow splitter, wherein the flow splitter defines at least one passage extending between the first and second volute regions.
  2. 2. The pump casing of claim l, wherein the at least one passage defined in the flow splitter is formed during a casting process.
  3. 3. The pump casing of claim l or 2, wherein the at least one passage is adapted to permit fluid to pass between the first and second volute regions when the pump casing is in use.
  4. 4. The pump casing of claim l or 2, wherein the at least one passage is adapted to be plugged to prevent fluid flowing therethrough between the first and second volute regions.
  5. 5. The pump casing of claim 4, wherein the at least one passage is adapted to be plugged subsequent to forming the casing by a casting process.
  6. 6. The pump casing of claim 4 or 5, wherein the at least one passage is adapted to be plugged by an insert.
  7. 7. The pump casing of claim 4 or 5, wherein the at S least one passage is adapted to be plugged during a casting process.
  8. 8. The pump casing of claim 7, wherein the at least one passage is adapted to be plugged by at least a portion of one or more casting cores retained in place within the at least one passage subsequent to the casting process.
  9. 9. The pump casing of claim 8, wherein a web of a casting core extending through the at least one passage is retained in place subsequent to a casting process.
  10. 1O. The pump casing of any preceding claim, wherein the casing further comprises a discharge branch in fluid communication with the volute.
  11. 11. The pump casing of claim LO, wherein the flow splitter extends from a region adjacent the discharge branch and into the volute.
  12. 12. The pump casing of claim 10 or 11, wherein the flow splitter extends from within the discharge branch and into the volute.
  13. 13. The pump casing of any preceding claim, wherein said casing is formed as a single component.
  14. 14. The pump casing of any one of claims 1 to 12, wherein the pump casing is formed in at least two lO components which are adapted to be secured together.
  15. 15. The pump casing of claim 14, wherein said pump casing is axially split.
  16. 16. The pump casing of claim 14, wherein said pump casing is radially split.
  17. 17. The pump casing of claim 16, wherein said pump casing is radially split in a vertical plane.
  18. 18. The pump casing of claim 16, wherein said pump casing is split in a horizontal plane.
  19. 19. The pump casing of claim 16, 17 or 18, wherein said pump casing is radially split and one of the at least one passage defined by the flow splitter is aligned with the plane of the radial split.
  20. 20. The pump casing of any preceding claim, wherein the S at least one passage extends across a portion of the flow splitter.
  21. 21. The pump casing of any preceding claim, wherein the at least one passage substantially extends the width of lO the flow splitter.
  22. 22. The pump casing of any preceding claim, wherein the at least one passage extends across a central region of the flow splitter.
  23. 23. The pump casing of any preceding claim, wherein the at least one passage extends from an edge of the flow splitter.
  24. 24. The pump casing of any preceding claim, wherein the flow splitter defines a plurality passages extending between the first and second volute regions.
  25. 25. The pump casing of any preceding claim, wherein the flow splitter defines two passages. 15
  26. 26. The pump casing of any preceding claim, wherein the volute is adapted to house a pump impeller.
  27. 27. The pump casing of any preceding claim, adapted for use in a centrifugal pump assembly.
  28. 28. The pump casing of claim 27, adapted for use in a single-stage centrifugal pump assembly.
    lO
  29. 29. The pump casing of claim 27, adapted for use in a multiple-stage centrifugal pump.
  30. 30. The pump casing of claim 29, wherein the volute is a discharge volute of the multiple-stage centrifugal pump.
  31. 31. The pump casing of any preceding claim, wherein the volute is a double volute.
  32. 32. A pump comprising a pump casing according to any preceding claim.
  33. 33. A pump casing comprising a double volute at least partially defined by a flow splitter, wherein said flow splitter defines at least one passage therein extending between opposing faces of the flow splitter.
  34. 34. A method of manufacturing a pump casing, said method comprising the step of utilising a casting core in a moulding process, the casting core being formed by at least two portions connected together by a web, wherein a pump casing flow splitter is formed between the two portions of the casting core, and the web age extends through said flow splitter between opposing surfaces thereof.
  35. 35. The method of claim 34, wherein one web is provided.
  36. 36. The method of claim 34, wherein a plurality of webs are provided.
GB0513008A 2004-07-08 2005-06-27 Double volute casing for a centrifugal pump Withdrawn GB2416003A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0415301A GB0415301D0 (en) 2004-07-08 2004-07-08 Pump casing

Publications (2)

Publication Number Publication Date
GB0513008D0 GB0513008D0 (en) 2005-08-03
GB2416003A true GB2416003A (en) 2006-01-11

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Family Applications (2)

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GB0415301A Ceased GB0415301D0 (en) 2004-07-08 2004-07-08 Pump casing
GB0513008A Withdrawn GB2416003A (en) 2004-07-08 2005-06-27 Double volute casing for a centrifugal pump

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB0415301A Ceased GB0415301D0 (en) 2004-07-08 2004-07-08 Pump casing

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2182220A1 (en) 2008-10-28 2010-05-05 Nederlandse Organisatie voor toegepast-natuurwetenschappelijk Onderzoek TNO Turbo machine and method to reduce vibration in turbo machines.
CN102606533A (en) * 2012-03-21 2012-07-25 江苏大学 Three-diffusion-tube volute structure enabling centrifugal pump to achieve radial force balance
CN103016404A (en) * 2012-12-06 2013-04-03 大耐泵业有限公司 Symmetric double-outlet vortex chamber pump body of vertical single-stage single-suction submerged centrifugal pump
CN103982468A (en) * 2014-04-28 2014-08-13 北京中水科水电科技开发有限公司 Centrifugal pump volute
US20140230431A1 (en) * 2013-02-20 2014-08-21 Ford Global Technologies, Llc Supercharged internal combustion engine with two-channel turbine and method for operating an internal combustion engine of said type
CN108160936A (en) * 2018-02-11 2018-06-15 常州中车汽车零部件有限公司 A kind of small-sized volute casting mould and casting method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1488189A (en) * 1974-08-01 1977-10-05 Hydro Tech Corp Water jet marine propulsion units
GB2069606A (en) * 1980-01-19 1981-08-26 Klein Schanzlin & Becker Ag Centrifugal pump having a double volute casing
EP0597815A1 (en) * 1992-11-13 1994-05-18 ITT Flygt Aktiebolag A pump housing device
EP0902192A2 (en) * 1997-09-15 1999-03-17 KSB Aktiengesellschaft Volute casing pump
JP2001336499A (en) * 2000-05-24 2001-12-07 Hitachi Ltd Double volute type casing

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1488189A (en) * 1974-08-01 1977-10-05 Hydro Tech Corp Water jet marine propulsion units
GB2069606A (en) * 1980-01-19 1981-08-26 Klein Schanzlin & Becker Ag Centrifugal pump having a double volute casing
EP0597815A1 (en) * 1992-11-13 1994-05-18 ITT Flygt Aktiebolag A pump housing device
EP0902192A2 (en) * 1997-09-15 1999-03-17 KSB Aktiengesellschaft Volute casing pump
JP2001336499A (en) * 2000-05-24 2001-12-07 Hitachi Ltd Double volute type casing

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2182220A1 (en) 2008-10-28 2010-05-05 Nederlandse Organisatie voor toegepast-natuurwetenschappelijk Onderzoek TNO Turbo machine and method to reduce vibration in turbo machines.
CN102265040A (en) * 2008-10-28 2011-11-30 荷兰应用科学研究会(Tno) Turbo machine and method to reduce vibration in turbo machines
US8951005B2 (en) 2008-10-28 2015-02-10 Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno Turbo machine and method to reduce vibration in turbo machines
CN102265040B (en) * 2008-10-28 2015-06-24 荷兰应用科学研究会(Tno) Turbo machine and method to reduce vibration in turbo machines
CN102606533A (en) * 2012-03-21 2012-07-25 江苏大学 Three-diffusion-tube volute structure enabling centrifugal pump to achieve radial force balance
CN103016404A (en) * 2012-12-06 2013-04-03 大耐泵业有限公司 Symmetric double-outlet vortex chamber pump body of vertical single-stage single-suction submerged centrifugal pump
CN103016404B (en) * 2012-12-06 2015-12-23 大耐泵业有限公司 The vertical single stage single suction submerged centrifugal pump symmetric double symmetric double-outlet vortex chamber pump housing
US20140230431A1 (en) * 2013-02-20 2014-08-21 Ford Global Technologies, Llc Supercharged internal combustion engine with two-channel turbine and method for operating an internal combustion engine of said type
US9366177B2 (en) * 2013-02-20 2016-06-14 Ford Global Technologies, Llc Supercharged internal combustion engine with two-channel turbine and method
CN103982468A (en) * 2014-04-28 2014-08-13 北京中水科水电科技开发有限公司 Centrifugal pump volute
CN108160936A (en) * 2018-02-11 2018-06-15 常州中车汽车零部件有限公司 A kind of small-sized volute casting mould and casting method

Also Published As

Publication number Publication date
GB0415301D0 (en) 2004-08-11
GB0513008D0 (en) 2005-08-03

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